<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        // undefined
        // null
        // NaN
        // 0
        // '' (empty string)
        // false
        // 以上6种false
    </script>
</body>

</html>